Hello!
Here, the tense used is the past imperfect tense.
Hence, the correctly written sentence will be :

Answer:
It helps people express themselves, and might let them get rid of bottled up emotions that they have been holding back
Explanation:
Answer:naturals= people who have natural talent
grinds= people who worked harder than everyone else
Explanation:
Ericsson found that either way, to truly achieve success you must put in the preparation